CN112709799A

CN112709799A - Hydrodynamic torque converter with torsional vibration damper and motor vehicle comprising same

Info

Publication number: CN112709799A
Application number: CN201911023452.0A
Authority: CN
Inventors: 李茂辉; 孟腾; 胡勋; 殷英
Original assignee: Faroeco Torque Converter Nanjing Co ltd
Current assignee: Faroeco Torque Converter Nanjing Co ltd
Priority date: 2019-10-25
Filing date: 2019-10-25
Publication date: 2021-04-27

Abstract

The present disclosure relates to a hydrodynamic torque converter for a motor vehicle, comprising: a cover driven by a drive member on an engine side of the motor vehicle to rotate about a rotational axis of the torque converter; a pump wheel connected in a rotationally fixed manner with the cover; a turbine driven to rotate about an axis of rotation to output torque to an input shaft of a transmission of a motor vehicle; a piston disc including friction surfaces that are actuatable to switch the torque converter between a fluid transmission mode and a mechanical transmission mode in which the friction surfaces abut the cover such that the cover rotates integrally with the piston disc; at least one torsional vibration damper held between the piston disc and the turbine, comprising at least one spring. The piston disc is provided with an integrally formed annular groove for receiving and guiding the spring and retaining the spring by means of the worm gear. The disclosure also relates to a motor vehicle comprising said torque converter.

Description

Hydrodynamic torque converter with torsional vibration damper and motor vehicle comprising same

Technical Field

The present disclosure relates to a torque converter with a torsional vibration damper. In particular, a guide portion for guiding a spring of the torsional vibration damper is provided on a piston disc of the torque converter. The disclosure also relates to a motor vehicle comprising such a hydrodynamic torque converter.

Background

In general, a torque converter is provided between an engine and a transmission of an automatically shifting motor vehicle. The torque converter is used for transmitting driving power of an engine to a transmission, and can play a role in transmitting torque and converting torque. The hydrodynamic torque converter comprises a cover driven by a drive member on the engine side, a pump impeller connected in a rotationally fixed manner with the cover, and a turbine wheel connected to the transmission input shaft, and can be switched between a fluid transmission mode and a mechanical transmission mode by means of a piston disc. During a launch phase of the motor vehicle, the torque converter operates in a fluid transmission mode. At this time, the impeller of the torque converter drives the turbine wheel through fluid (usually oil). After the engine reaches a higher speed, the torque converter switches to a mechanical transmission mode. In the mechanical drive mode, torque is mechanically transferred from the cover to the turbine through the piston disc and/or other drive mechanism without passing through the impeller.

The torque produced at the motor vehicle engine is generally not constant. In particular, in mechanical transmission modes, such non-constant torque may be transmitted into the transmission, causing vibrations of the transmission gearbox and thus generating particularly undesirable noise or bumps, etc. In order to reduce the adverse effects of vibrations and to improve the driving comfort of motor vehicles, it is known to provide torsional vibration dampers in torque converters. Torsional vibration dampers may allow for the absorption and mitigation of vibrations generated by an automotive engine. Torsional vibration dampers are typically disposed between the piston disc and the turbine and transmit torque therebetween.

Chinese patent CN104235301B discloses a torque converter with a torsional damper mounted on the piston disc. A retaining plate for retaining the spring is fixed to the piston disc by rivets. In addition, a radially extending holding portion is formed on the holding plate, and a plurality of transmission claws are welded and fixed to the turbine for transmitting torque between the piston disc and the turbine.

Japanese patent application JPH06147294A also discloses a similar torque converter with a torsional damper mounted on the piston disc. An annular drive disk, which retains the springs and transmits torque, is secured to the piston disk by rivets, and a plurality of tabs for transmitting torque are fixedly provided on the turbine.

As mentioned above, torsional vibration dampers are typically arranged between the piston disc and the turbine. However, it is also conceivable to arrange the torsional damper at other positions in the torque transmission path of the torque converter. US patent application US6056093A discloses a hydrodynamic torque converter in which a torsional damper is provided between the turbine and the output hub. Specifically, a cover plate element for holding the springs of the torsional damper is secured to the turbine housing and includes a protrusion that engages the piston plate to transmit torque to the turbine. The output hub includes a radially outwardly integrally extending flange that, together with a projection on the turbine housing, retains the spring in a circumferential direction and transmits torque.

Therefore, in the conventional torque converter, it is generally necessary to provide a plurality of holding elements and torque transmission elements in order to hold the torsional damper and transmit torque. This makes the manufacturing process of the torque converter complicated and easily damaged. Further, the retaining element and the torque transmitting element arranged in the axial direction increase the axial dimension of the torque converter, compressing space for mounting other torque transmitting components such as the transmission.

Disclosure of Invention

Accordingly, the present disclosure is directed to solving the above-mentioned problems occurring in the conventional torque converter, and an object thereof is to provide a torque converter in which a piston disc is provided with a guide portion for guiding a spring of a torsional damper, which can also cooperate with a turbine to retain the spring and transmit torque, so that it is not necessary to additionally provide a dedicated retaining element and a torque transmitting element. The torque converter with the structure can save the manufacturing cost, reduce the axial size and increase the installation space of other torque transmission components.

The object is achieved by a torque converter including a torsional vibration damper according to one embodiment of the present disclosure, comprising: a cover rotationally driven by a drive member on an engine side of the motor vehicle so as to rotate about a rotational axis of the torque converter; a pump wheel rotationally fixedly connected with the cover so as to rotate together with the cover; a turbine driven to rotate about the axis of rotation and transmit torque to an input shaft of a transmission of a motor vehicle; a piston disc including a friction surface, the piston disc being actuatable to operatively switch the torque converter between a fluid transmission mode in which rotation of the pump impeller about the axis of rotation generates a flow of fluid to drive the turbine wheel and a mechanical transmission mode in which the friction surface bears against the cover such that the cover rotates integrally with the piston disc; at least one torsional vibration damper retained between the piston disc and the turbine and transmitting torque from the piston disc to the turbine, the torsional vibration damper including at least one spring. The piston disc is provided with an annular groove formed integrally therewith, by which the compression and return of the spring is guided during torque transmission. Additionally, the piston disc may cooperate with the turbine to retain the spring of the torsional damper in the annular groove.

Since the piston disc itself can guide the spring and cooperate with the turbine to hold the torsional damper, there is no need to provide special torsional damper holding and guiding components in the torque converter. This design thus allows reducing the size, in particular the axial size, of the torque converter, reducing the number of components required, reducing the manufacturing costs of the torque converter and making its installation simpler.

A torque converter according to the present disclosure may also have one or more of the following features, alone or in combination.

According to one embodiment of the present disclosure, the annular groove has a generally rectangular cross-sectional shape including an inner sidewall on a radially inner side, an outer sidewall on a radially outer side, and a floor connecting the inner sidewall and the outer sidewall. Preferably, the outer side wall of the annular groove constitutes the radially outer edge of the piston disc, that is to say the annular groove is located at the radially outermost portion of the piston disc. The bottom surface of the annular groove is a flat bottom surface, and the friction surfaces are provided on axially opposite surfaces of the bottom surface. With this arrangement, it is not necessary to form a projection on the piston disc, which projection is dedicated to the arrangement of the friction surface, thereby saving the process steps in manufacturing the piston disc.

According to a preferred embodiment of the present disclosure, the end of the outer side wall of the annular groove comprises an inward bead. The inward bead may narrow the opening of the annular groove. For example, the opening of the annular groove can be reduced by crimping to just fit the spring. This design makes it possible to both mount the spring and facilitate preventing it from coming out of the annular groove together with the turbine.

Alternatively, the annular groove may have other cross-sectional shapes. For example, the annular groove is semi-circular in cross-section and has a diameter slightly larger than the diameter of the spring of the torsional vibration damper to facilitate receiving and retaining the spring. In this configuration, the friction surface may be provided elsewhere on the piston disc.

According to one embodiment of the disclosure, the annular groove is provided with one or more spring drivers, which may carry spring seats to drive the springs received in the annular groove to transmit torque. That is, the piston disc itself is able to drive the spring without the need to additionally provide a drive disc or other torque transmitting component dedicated to driving the spring. This can further reduce the number of parts of the torque converter, reducing the manufacturing cost.

Optionally, the spring drive portion includes an inner boss projecting radially outward on an inner sidewall of the annular groove, and an outer boss projecting radially inward on an outer sidewall of the annular groove. The inner boss and the outer boss face each other in a radial direction. That is, the circumferential positions of the inner boss and the outer boss are the same. The inner and outer bosses thus define a narrowing of the annular groove, the width of which is less than the diameter of the spring. The spring seat may abut corresponding side walls of the inner and outer bosses. Preferably, the corresponding side walls of the inner and outer bosses lie in the same radial plane passing through the rotational axis of the torque converter. That is, the inner and outer bosses correspond to the same central angle of the piston disc in plan view. From this, the bottom surface that leans on the spring seat portion of the corresponding lateral wall of inner boss and outer boss also lies in this radial plane for the spring seat portion can evenly atress, is favorable to strengthening the stationarity of moment of torsion transmission.

Alternatively, the spring drive may be a tab extending from the inner and/or outer side wall of the annular groove inwardly of the annular groove. The side walls of the tabs carry the seats of the springs to drive the springs and transmit the torque. This arrangement simplifies the design of the spring drive and reduces the number of steps required to manufacture the piston disc.

According to one embodiment of the present disclosure, the annular groove is provided with three spring driving portions evenly distributed in a circumferential direction. The three spring drivers may divide the annular groove into three groove segments, each of which may accommodate one spring. Accordingly, the torsional vibration damper includes three springs. It is contemplated that the annular groove could also be provided with a different number of spring drives, such as two spring drives, four spring drives, five spring drives, or more. Accordingly, the number of springs included in the torsional vibration damper is also different accordingly.

The torque converter may also include a plurality of torsional vibration dampers to further enhance the damping effect. For example, the torsional vibration damper located on the radially outer side is a first torsional vibration damper, and the torque converter further includes a second torsional vibration damper located on the radially inner side. The second torsional vibration damper may have a similar configuration to the first torsional vibration damper.

According to one embodiment of the present disclosure, the piston disc of the torque converter is integrally manufactured by stamping. In particular, the annular groove is formed by stamping in the axial direction perpendicular to the plane of the piston disc. The punch used during the stamping process is selected to be a shape suitable for forming the annular recess. After the annular groove is punched out, the spring driving portion may be punched out in a radial direction perpendicular to a sidewall of the annular groove. The spring drive may be formed as a boss without breaching the side wall, or as a tab with breaching the side wall. After stamping, the thickness of some parts of the piston disc will be reduced accordingly. Preferably, in order to increase the strength of the piston disc, the piston disc may be strengthened by a heat treatment process after stamping.

The present disclosure also relates to a motor vehicle comprising a hydrodynamic torque converter as described above.

The above features and advantages and other features and advantages of the present teachings are readily apparent from the following detailed description of the best modes for carrying out the present teachings when taken in connection with the accompanying drawings.

Drawings

FIG. 1 is a schematic illustration in partial cutaway of a torque converter according to one embodiment of the present disclosure.

Fig. 2A-2C illustrate a piston disc according to one embodiment of the present disclosure, wherein fig. 2A illustrates a face of the piston disc facing a turbine, fig. 2B illustrates a face of the piston disc facing a cover, and fig. 2C illustrates a cross-sectional view of an annular groove portion of the piston disc.

Fig. 3A and 3B illustrate in detail the spring drive portion of the piston disc shown in fig. 2A-2C.

FIG. 4 illustrates a schematic partial cut-away view of a torque converter according to another embodiment of the present disclosure.

In the various figures, identical or similar components are denoted by the same reference numerals.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present disclosure more clear, the technical solutions of the embodiments of the present disclosure will be described below in detail and completely with reference to the accompanying drawings of the embodiments of the present disclosure.

Unless otherwise defined, technical or scientific terms used herein shall have the ordinary meaning as understood by one of ordinary skill in the art to which this disclosure belongs. The use of the terms "a" and "an" or "the" and similar referents in the description and claims of the present disclosure also do not denote a limitation of quantity, but rather denote the presence of at least one. The word "comprising" or "comprises", and the like, means that the element or item preceding the word covers the element or item listed after the word and its equivalents, but does not exclude other elements or items. The directions "axial direction", "radial direction", and "circumferential direction" are defined with respect to the rotation axis RO of the torque converter, i.e., the direction in which the rotation axis RO extends, the radial direction is a direction perpendicular to the rotation axis RO, and the circumferential direction is a circumferential direction around the rotation axis RO.

FIG. 1 is a schematic illustration in partial cutaway of a torque converter according to one embodiment of the present disclosure. For clarity, various components of the structure of the torque converter that are not relevant to understanding the technical aspects of the present disclosure have been omitted.

As shown in fig. 1, the torque converter includes a cover 1, a pump impeller 2, a turbine runner 3, a piston disc 4, a torsional damper 5 disposed between the turbine runner and the piston disc, and a stator 6. The cover 1 is driven in rotation by a drive member on the engine side of the motor vehicle, while the pump wheel 2 is connected rotationally fixed to the cover 1, for example by welding. Thus, torque is input to the torque converter through the cover 1 and the impeller 2. The turbine 3 is driven to rotate about the rotation axis RO and transmits torque to an input shaft of a transmission of a motor vehicle through the turbine hub 30, i.e., torque is output from the torque converter through the turbine 3 and the turbine hub 30.

The torque transmission from the cover 1 and the pump impeller 2 to the turbine wheel 3 can be switched between both a fluid transmission mode and a mechanical transmission mode depending on the running condition of the motor vehicle. This switching is achieved by actuating (e.g. hydraulically actuating) the piston disc 4 in the axial direction.

Specifically, the pump impeller 2, the turbine runner 3, and the stator 6 define an annular passage in which the working fluid of the torque converter circulates. In the fluid transmission mode, the piston disc 4 is actuated out of contact with the cover 1, being free to rotate relative to each other. At this time, the rotation of the pump impeller 2 about the rotation axis RO causes the flow of the working fluid, which in turn drives the turbine 3. That is, in the fluid transmission mode, the torque transmission path of the torque converter is: torque input → cover 1 → impeller 2 → (working fluid) → turbine 3 → turbine hub 30 → torque output. The solid lines in fig. 1 show the torque transmission paths in the fluid transmission mode.

In the mechanical transmission mode, the piston disc 4 is actuated towards the cover 1 such that the friction surface 41 abuts the cover 1. The piston disc 4 and the cap 1 rotate as a unit by frictional contact therebetween. The piston disc 4 transmits torque to the turbine 3 through the torsional vibration damper 5. That is, in the mechanical transmission mode, the torque transmission path of the torque converter is: torque input → cap 1 → piston disc 4 → (torsional damper 5) → turbine 3 → turbine hub 30 → torque output. The torque transmission paths in the mechanical transmission mode are shown in dashed lines in fig. 1.

To transmit torque and to mitigate torque variations transmitted to the torque output, the torsional vibration damper 5 includes one or more springs 51, such as helical compression springs. The piston disc 4 compresses the spring 51, which spring 51 further exerts a spring force to the turbine 3, thereby achieving a torque transmission from the piston disc 4 to the turbine 3. The piston disc 4 is provided with an annular groove 42 for receiving and guiding said spring 51, which annular groove 42 is formed integrally with the piston disc. The compression and return of the spring 51 is guided by the annular groove 42 during torque transmission.

Fig. 2A shows the side of the piston disc 4 facing the turbine 3, fig. 2B shows the side of the piston disc 4 facing the cover 1, and fig. 2C shows a partial cross-sectional view of the piston disc 4. It can be seen that the annular groove 42 is recessed from the turbine 3 towards the cover 1. The annular groove 42 has a substantially rectangular cross-sectional shape including an inner side wall 42a located radially inward, an outer side wall 42b located radially outward, and a bottom surface 42c connecting the inner side wall 42a and the outer side wall 42 b. The annular groove 42 has a width slightly larger than the diameter of the spring 51 and is therefore adapted to accommodate the spring 51. The annular groove 42 is located radially outermost of the piston disc 4 such that its outer side wall 42b forms the radially outer edge of the piston disc 4. The bottom surface 42c of the annular groove 42 is flat and constitutes the portion of the piston disc 4 closest to the cover 1 in the axial direction. The frictional surface 41 is provided on an axially opposite surface of the bottom surface 42 c. With this arrangement, when the piston disc 4 is actuated towards the cover 1, the friction surface 41 first abuts the cover 1, thereby rotationally locking the piston disc 4 with the cover 1. Furthermore, the positioning of the annular groove 42 at the radially outermost portion of the piston disc 4 also positions the friction surface 41 at the radially outermost portion of the piston disc 4, facilitating torque transfer between the piston disc 4 and the cover 1. By this design, no protrusions are required on the piston disc 4, which protrusions are dedicated to the arrangement of the friction surfaces 41, thereby saving the process steps in manufacturing the piston disc 4.

As shown in fig. 2C, the end of the outer side wall 42b of the annular groove 41 includes an inward bead 43, i.e., winding from the outer side wall 42b toward the inner side wall 42 a. Thus, the inward bead 43 may narrow the opening of the annular groove 41. For example, the opening of the annular recess 41 can be narrowed by a bead 43 to just fit the spring. This design makes it possible to facilitate the mounting of the spring and to prevent, together with the turbine 3, the spring from coming out of the annular groove 41.

Although not shown in the drawings, it is envisaged by a person skilled in the art that the annular groove 41 may also have a cross-section of other shapes. For example, the annular groove 41 may be semi-circular in cross-section, with a diameter slightly larger than the diameter of the spring 51 of the torsional damper 5, so as to facilitate the accommodation and retention of said spring 51.

As shown in fig. 2A, the annular groove 41 is further provided with three spring driving portions 44, and the annular groove 41 is divided into three sections, one spring 51 being placed in each section. Although not shown, a different number of spring drives is also conceivable. The spring drive 44 defines a narrowing of the annular recess 41 having a width less than the diameter of the spring 51. Thus, the spring driving part 44 may carry the seat of the spring 51, thereby driving the spring 51 to transmit torque. In this way, the piston disc 4 itself is able to drive the spring 51 without the need to additionally provide a drive disc or other torque transmitting component dedicated to the drive spring.

Fig. 3A shows one spring drive 44 in detail. In the illustrated embodiment, the spring drive portion 44 includes an inner boss 44a projecting radially outward on the inner side wall 42a of the annular groove 41, and an outer boss 44b projecting radially inward on the outer side wall 42b of the annular groove 41. The inner boss 44a and the outer boss 44b face each other in the radial direction. The inner boss 44a and the outer boss 44b of the same spring driving portion 44 are at the same angular position.

The inner boss 44a and the outer boss 44b may have different circumferential lengths. As shown in fig. 3B, the inner and outer bosses 44a, 44B correspond to the same central angle of the piston disc 4. Thus, the corresponding sidewalls of the inner boss 44a and the outer boss 44b lie on the same radial plane passing through the rotational axis RO of the torque converter. The spring seats against the corresponding side walls of the inner and

outer bosses

44a, 44b are thus also located in this radial plane. Therefore, the spring seat part can be stressed uniformly, and the stability of torque transmission is enhanced.

Although not shown in the drawings, it is contemplated by those skilled in the art that the spring drive 44 may have other forms. For example, the inner sidewall and/or a portion of the outer sidewall of the annular groove 42 form a tab that extends inward of the annular groove, leaving an opening or aperture in the corresponding sidewall of the annular groove 42. The tab may form a spring drive.

Fig. 4 shows a hydrodynamic torque converter comprising two torsional vibration dampers to further enhance the damping effect. The torsional vibration damper 5 described above is located radially outward and is the first torsional vibration damper. The second torsional vibration damper 7 is located radially inwards, has a similar construction to the first torsional vibration damper, and the piston disc 4 is arranged with an additional annular groove at the radially inner side for the second torsional vibration damper 7.

One particular advantage with the torque converter described above is that the piston disc 4 can be manufactured by stamping. After the body of the piston disc 4 is made, the annular groove 42 on the piston disc 4 may be formed by stamping the piston disc 4, and the spring drive 44 may be formed by stamping the side wall of the annular groove 42. In particular, the spring drive 44 may be formed in the form of a boss without breaking the side wall of the annular groove, and the spring drive 44 may be formed in the form of a tab with breaking the side wall. That is, the body of the piston disc 4 and the various formations thereon can be manufactured by stamping, thereby eliminating the need for additional processes and the need for special torsional damper retainer and torque transmitting elements. Preferably, after stamping, the piston disc 4 may also be strengthened by a heat treatment process to compensate for the adverse effect of the stamping process on the strength of the piston disc.

It is to be understood that the structures described above and shown in the drawings are merely examples of the present disclosure, which can be substituted with other structures exhibiting the same or similar function for achieving the desired end result. Furthermore, it should be understood that the embodiments described above and shown in the drawings are to be regarded as merely constituting non-limiting examples of the present disclosure and that it can be modified in a number of ways within the scope of the patent claims.

Claims

1. A torque converter for a motor vehicle comprising:

a cover (1) driven by a drive member on the engine side of a motor vehicle to rotate about a rotational axis (RO) of a torque converter;

a pump wheel (2) which is connected to the cover (1) in a rotationally fixed manner;

a turbine (3) driven to rotate about the rotation axis (RO) to output torque to an input shaft of a transmission of a motor vehicle;

a piston disc (4) comprising a friction surface (41), the piston disc (4) being actuatable to operatively switch the torque converter between a fluid transmission mode in which rotation of the pump impeller (2) about the axis of Rotation (RO) generates a flow of fluid, thereby driving the turbine wheel (3), and a mechanical transmission mode in which the friction surface (41) bears against the cover (1) such that the cover (1) rotates integrally with the piston disc (4);

at least one torsional vibration damper (5) which is held between the piston disc (4) and the turbine (3) and which transmits torque from the piston disc (4) to the turbine (3), the torsional vibration damper (5) comprising at least one spring (51),

characterized in that the piston disc (4) is provided with an annular groove (42) formed integrally with the piston disc (4), the annular groove (42) being intended to receive and guide the spring (51), and the spring (51) being held in the annular groove (42) by the turbine (3).

2. A hydrodynamic torque converter according to claim 1,

the annular groove (42) includes an inner side wall (42a) located radially inward, an outer side wall (42b) located radially outward, and a bottom surface (42c) connecting the inner and outer side walls.

3. A hydrodynamic torque converter according to claim 2,

the outer side wall (42b) forms the radial outer edge of the piston disc (4).

4. A hydrodynamic torque converter according to claim 3,

the bottom surface (42c) is flat, and friction surfaces (41) are provided on axially opposite surfaces of the bottom surface.

5. A hydrodynamic torque converter according to any one of claims 2 to 4,

the end of the outer side wall (42b) of the annular groove (42) comprises an inward bead (43).

6. A hydrodynamic torque converter according to any one of claims 2 to 4,

the annular groove (42) is provided with one or more spring drives (44).

7. A hydrodynamic torque converter according to claim 6,

the spring drive portion (44) includes an inner boss (44a) projecting radially outward on an inner side wall (42a) of the annular groove, and an outer boss (44b) projecting radially inward on an outer side wall (42b) of the annular groove, the inner boss (44a) and the outer boss (44b) facing each other in a radial direction.

8. A hydrodynamic torque converter according to claim 7,

the corresponding side walls of the inner boss (44a) and the outer boss (44b) lie on the same radial plane passing through the rotational axis (RO) of the torque converter.

9. A hydrodynamic torque converter according to claim 5,

the spring drive portion (44) is a tab that extends from the inner side wall (42a) and/or the outer side wall (42b) of the annular groove (42) to the interior of the annular groove.

10. A hydrodynamic torque converter according to claim 5,

the annular groove (42) is provided with three spring driving portions (44) which are uniformly distributed in the circumferential direction.

11. A hydrodynamic torque converter according to any one of claims 1 to 4,

the torsional vibration damper (5) is a first torsional vibration damper, and the torque converter further comprises a second torsional vibration damper (7) located radially inside the first torsional vibration damper (5).

12. A hydrodynamic torque converter according to any one of claims 1 to 4,

the piston disc (4) is produced in one piece by stamping.

13. A hydrodynamic torque converter according to claim 12,

the piston disc (4) is strengthened by a heat treatment process after stamping.

14. A motor vehicle comprising a hydrodynamic torque converter according to any one of the preceding claims.